1. Field of the Invention
The present invention relates to a flash unit for a camera, and particularly relates to a pop-up flash unit for a camera that is movable between a projected position and a retracted position.
2. Description of Prior Art
Flash units for providing artificial illumination during photographic exposures under conditions of low ambient scene light intensity are well known in the art. However, with more recent cameras that have a large sized taking lens to achieve a high zoom ratio, a built-in unit is generally insufficient to meet the performance requirements. Furthermore, since electronic viewfinders (EVF) are increasingly incorporated in cameras instead of standard optical viewfinders (OVF), the camera design correspondingly becomes increasingly compact, which results in limited interior space available in the camera. In addition, with the current trend of cameras toward compactness, the relative closeness of the flash unit and the taking lens can cause an undesirable phenomenon known as “red-eye” to occur. This effect causes the pupils of the eyes of a person being photographed to appear as red dots in a print made from the color negative. Accordingly, to save the interior space of the camera and to reduce the occurrence of red-eye during flash picture-taking, a pop-up flash unit is desired that is pivotally connected to the body housing of the camera to be popped up from the body housing for use and popped down for storage. When popped up, the pop-up flash unit increases the flash-to-lens distance and therefore makes red-eye phenomenon less likely to occur. The pop-up flash unit is manually raised or automatically rises from the camera body when needed.
Various pop-up flash units have conventionally been proposed.
For example, in U.S. Pat. No. 5,930,534, a pop-up flash unit is disclosed that is pivotally connected to the camera body housing. The camera body housing has a protruding portion that forms a film roll chamber, and the pop-up flash unit has a flash housing defining a cavity for receiving the protruding portion when the pop-up flash unit is popped down to the body housing, thereby integrating the flash housing with the body housing. Such a pop-up flash unit occupies a large space and significantly increases the longitudinal dimension of the camera, which deviates from the current compact trend.
U.S. Pat. No. 5,066,967 discloses a pop-up flash unit that is retained by engagement in the state of being urged in a pop-up direction, and for a pop-up operation, the flash unit is released from the retention by engagement by means of an electromagnet. Such a conventional pop-up flash unit, however, has a number of disadvantages. For example, since a dedicated actuator such as the electromagnet is needed for initiating the pop-up operation of the flash unit, an increase in cost cannot be avoided and the mechanism cannot be simplified. Also, if a flash zooming mechanism is to be added, an additional motor or the like is needed and the size of the camera increases.
U.S. Pat. No. 6,104,882 discloses a pop-up flash unit that has a flash-light emitting block connected to the camera body through a pair of linking mechanisms. Each of the linking mechanisms is composed of a primary lever, an L-shaped lever and a C-shaped lever. The flash-light emitting block is moved up and down through pivots provided thereon when the pair of primary levers swings. During this swinging movement of the pair of primary levers, the position and posture of the flash-light emitting block are controlled by the pair of L-shaped levers and the pair of C-shaped levers. Since such a linking mechanism is provided with a plurality of levers and pivots that are very complex in their movements, malfunctions may occur or the levers may get stuck during movement between the projected position and the retracted position.
Accordingly, an improved pop-up flash unit is desired to overcome the above-mentioned disadvantages in prior art.